232 TEKTH ANNUAL REPORT 



The body passes without marked transition into the abdomen which 

 is abnormally shortened; caudal stylets very short as is the last segment 

 of the abdomen; setae exactly as in C. parens with which it was found; 

 antennae eleven-jointed; formula — ^^ — ^^ -- ^ — — ■ a semi-cir- 

 cular series of spines upon the basal joint; fifth foot obsolescent, the 

 three spines appearing to spring directly from the last thoracic seg- 

 ment which also bears a series of teeth; egg-sac reaching to base of 

 abdomen, with rather numerous eggs; feet heavily spined on one mar- 

 gin; length iVo c^i J male i^ cm. 



This species, together with all others of this sort with eleven-jointed 

 antennae, is perhaps but an immature and abnormally modified form 

 of some of the common species If this be true the rarity of these 

 nominal species is explained. C. minutus, Claus, is certainly but a lar- 

 yal form, as is shown by the two-jointed branches of swimming feet. 



Section with S-jointed Antennae 



CYCLOPS CRASSICORNIS, MiUler. 



(Plate IV, figs. 9-U.) 



Bibliography. 



Cyclops crassicornis, Muller, Entomostraca. 



Sars, Oversigt Ferskvands Copepoder. 

 U/janin, Reise in Turkestan. 

 Brady, British Copepoda. 

 pauper, Fric, Die Krustenthiere Bohemens. 

 ? magniceps, Lilljeborg, De crustaceis ex ordinibus tribus, etc. 



A small species characterized by its small size and the eight-jointed 

 antennae; body depressed and passing gradually, into the rather uni_ 

 form abdomen; first cephalothoracic joint large; abdomen rather slen- 

 der; stylets of moderate length, spined along the outer margin some- 

 what as in C. serrulatus; outer seta lance-shaped, short; the next one 

 as long as stylets and last two segments; the following one nearly 

 twice as long; inner one very small; last joint of abdoman spined; the 

 preceding one fringed on distal margin with weak setae; antennae 



short, not reaching the base of first segment; formula — — ' ^^ ^- 



^^ —; the basal joint with a semi-circular set of fine bristles, and with 

 the following is furnished with pectinate setae; second antennae short; 

 terminal joint short, with two curved, strong spines and other weaker 

 ones; fifth feet small one-jointed with three unequal spines, bordered 



