24 University of California Publications. [Zoology 



6. Conchoecia miilleri nov. uom. 



PI. V, figs. 5-7; pi. VI, figs. 1-5. 

 1890. Conchoecia striata, Mliller, p. 270, pi. XXVIII, figs. 12-18. 



Shell rather thin but firm; transparent, with distinct lonoi- 

 tiidinal striae and a few small irregular markings along- the pos- 

 terior margin ; shell of female somewhat higher behind than in 

 front, twice as long as g:reatest heig:ht; that of male about as 

 high in front as behind, a little moi-e than twice as long as high; 

 in both sexes the dorsal margin is nearly straight, with a depres- 

 sion near the middle; each valve with a short, strong, spinous 

 projection at the postero-dorsal angle ; anterior margin broadly 

 rounded, passing over gradually into the ventral margin ; pos- 

 tero-ventral curvature more abrupt ; rostrum broad, with a blunt 

 apex ; rostral sinus wide and rather shallow. 



Capitulum of frontal organ of male dilated and truncated at 

 the base, with a blunt apex; posterior two-thirds hispid with 

 sparsely set hairs; capitulum of female similar but not dilated 

 so much nor so distinctly truncated at the base and a little more 

 pointed at the apex. 



The first seta of the male antennule is longer than the other 

 two, and bears in the middle about twenty pairs of short, stout, 

 recurved spines; the third or posterior seta is slightly curved a 

 little beyond the middle and bears at this place a small lamina 

 which has a rough edge; beyond this lamina, on the oi)posite 

 side of the seta, are some minute spinules pointing forward. One 

 of the sensory setae is short, the other is curved at the base and 

 turned backward in opposition to the antennule. The antennule 

 of the female bears one long seta and four sensory ones which 

 are less than half as long. 



The hooked appendage of the secondary branch of the male 

 antenna is strongly but regularly curved, forming a rather nar- 

 row arch ; the outer end is dilated and bears a small, blunt, tooth- 

 like process. The mammillary process is blunt in the male but 

 sharper pointed in the female. In the male the basal portion of 

 the third sensory seta of the secondary branch is slightly enlarged 

 and bears minute hairs; each of the three sensory setae of the 



