AET. 18 SYNOPSIS OF CALANOID CRUSTACEA MAESH 25 



furca is Mrmed with an external seta instead of a spine as in the 

 American species of Efischura. The fifth foot has seven spines in- 

 stead of five or six as in tj'pical species. From the locality of 

 Pearse's collection it would seem probable that he had E, norden- 

 sMoldi., but the structure of the fifth foot would seem to negative 

 this opinion. 



Genus HETEROCOPE Sars, 1863 



Eeterocope closely resembles Epischura. While the form and seg- 

 mentation of the cephalothorax are like Epischura, the abdomen of 

 the female is 3-segmented and that of the male 5-segmented; the 

 abdomen is not flexed in either sex. The furca, as in Epischura, 

 is armed with three setae, but the external spine of Epischura is 

 either lacking entirely or replaced by a short seta. The first and 

 second antennae, mandibles, maxillae, and maxillipeds are like those 

 in Epischura. The segmentation of the swimming feet is like that 

 in Epischura, but in some species the armature of spines is developed 

 asymmetrically. 



In the fifth foot of the female the terminal segment is armed 

 with two spines externally, with four hooklike teeth internally, and 

 a long terminal claw. Heterocope caspia has only three internal 

 spines and the terminal claw is simply a longer spine. 



The riglit fifth foot of the male has a 2-segmented exopod (one in 

 E. caspia and H. appendiculata) , which is not reflexed as in Epis- 

 chura. The terminal segment of the left foot has two lateral spines 

 on the external border and two terminal spines, one of which is 

 ordinarily elongated. 



As material was not available for a critical study of any of the 

 species of Europe and Asia, it did not seem wise, in this publication, 

 to make a detailed analysis of the species. Only one species has 

 been found in America and that is clearly distinct from those of 

 the eastern continents. 



H. caspia is very different from the other species, and it is pos- 

 sible that this should be considered as generically distinct. On 

 this account it has seemed best to add a brief description of this 

 species. 



Kiry TO THE SPECIES OF HETEKOCOPE 



1. Terminal segment of female fifth foot armed with six nearly 



equal spines caspia Sars 



Terminal segment of female fifth foot armed with six spines, 

 four internal and two external, and an elongated terminal 

 hook 2 



2. Exopod of male right fifth foot united with second segment of 



basipod in a long curved single segment appendiculata Sars 



Exopod of male right fifth foot composed of one or two segments 3 



