FREE BOOKS

Author's List




PREV.   NEXT  
|<   92   93   94   95   96   97   98   99   100   101   102   103   104   105   106   107   108   109   110   111   112   113   114   115   116  
117   118   119   120   121   122   123   124   125   126   127   128   129   130   131   132   133   134   135   136   137   138   139   140   141   >>   >|  
are covered on their inner sides continuously with spines. _Cirri._--The first pair is sometimes seated very distant from the second. The arrangement of the spines on the posterior cirri varies, to an unusual degree within the limits of the same genus. We have either the ordinary structure of anterior pairs, with single fine intermediate spines (as in _P. Kaempferi_ and _aurantia_), or we have the pairs increased by one or two additional longitudinal lateral rows, as in _P. eburnea_; or we have the front spines forming a single transverse row, as in _P. crassa_ and _P. fissa_, Pl. X, fig. 29, _a_. The segments in none of the species are protuberant; the anterior ramus of the second cirrus does not seem to be thicker than the posterior ramus, as is usually the case. The rami of the second, and of most of the other cirri, are unequal in length,--the anterior ramus, contrary to the ordinary rule, being longer in _P. eburnea_, _P. fissa_, and _P. crassa_, than the posterior ramus by several segments; I have hitherto observed this inequality only in the sessile genus Chthamalus. The _Caudal Appendages_ are small, uniarticulate, and always furnished with bristles. _Distribution._--Four out of the five species live attached to Crustacea in the European and Eastern warmer temperate and tropical oceans; the fifth species was found attached to the dead spines of an Echinus, off New Guinea. It is probable that several more species will be hereafter discovered. 1. PAECILASMA KAEMPFERI. Pl. II, Fig. 1. _P. valvis 5; carinae basi truncata et cristata: scutorum dentibus internis umbonalibus fortibus: tergorum acumine basali truncato, margini occludenti paene parallelo._ Valves 5; carina with a truncated and crested base; scuta with strong internal umbonal teeth; terga with the basal point truncated, almost parallel to the occludent margin. Maxillae with short thick spines in the notch under the two upper great spines; caudal appendages with scattered bristles on their summits, and along their whole outer margins. Japan; attached, in great numbers, to the upper and under sides of the _Inachus Kaempferi_ of De Haan, a slow-moving brachyourous crab, probably from deep water. British Museum. _General Appearance._--Capitulum rather compressed, narrow, and produced. Valves white, tinged with orange, smooth, moderately thin, occasionally with faint traces of striae radiating from the umb
PREV.   NEXT  
|<   92   93   94   95   96   97   98   99   100   101   102   103   104   105   106   107   108   109   110   111   112   113   114   115   116  
117   118   119   120   121   122   123   124   125   126   127   128   129   130   131   132   133   134   135   136   137   138   139   140   141   >>   >|  



Top keywords:

spines

 

species

 

anterior

 

posterior

 

attached

 

bristles

 

Kaempferi

 

eburnea

 
Valves
 

truncated


segments

 

crassa

 

ordinary

 

single

 

parallelo

 

traces

 

carina

 
striae
 

occludenti

 

margini


occasionally
 

umbonal

 

internal

 

truncato

 

strong

 

crested

 

acumine

 

valvis

 

radiating

 

carinae


PAECILASMA

 

KAEMPFERI

 

truncata

 
fortibus
 

tergorum

 
discovered
 

umbonalibus

 

internis

 

cristata

 

scutorum


dentibus

 
basali
 
margin
 
Inachus
 

compressed

 

numbers

 
narrow
 

moving

 

General

 

Museum