224 "TERRA NOVA" EXPEDITION. 



used twice previously, lie changed the name to Euvallentinia. His diagnosis is quoted 

 here iu full : — 



"A member of the Sphaerominae eubranchiatae, near to Paracerceis, Hansen, 1905', 

 but distinguished by not having the basal joint of the first antennae produced into an 

 acute process, the mandibles of the female not coalesced with the head, the exopod of 

 the uropods much shorter and narrower than the endopod, first gnathopod prehensile in 

 the male." 



In 1906 (l) Miss Richardson instituted a new genus, Cassidias, the type species of 

 which is C. argentinea, Eichardson. To this genus Miss Eichardson says that Cymodoce 

 darwinii, Cunningham,' should be referred, and she proceeds to point out the differences 

 between the two species. It seemed at first, therefore, as if the genera Cassidias and 

 Euvallentinia were synonymous, but, on going into the matter further, certain difficulties 

 appeared in the way of my accepting Miss Eichardson's interpretation of the generic 

 position of C. darwinii, and as a result of my observations I have been led to uphold 

 the validity of Stebbing's genus. If the diagnoses of Eichardson and Stebbing for their 

 two genera are compared, two points require further elucidation. Eichardson says of 

 Cassidias, " mouth parts of the female metamorphosed," and her figures of the first 

 maxilla and maxilliped of the female of C. argentinea support her statement. Stebbing 

 in defining Euvallentinia says, " the mandibles of the female not coalesced with the 

 head." This statement is not inconsistent with a metamorphosis of the mouth-parts in 

 egg-bearing females, for it is only in some few genera that the metamorphosis is so 

 complete as to lead to a complete fusion of the mandibles with the head, such as 

 Hansen describes in the genera Cerceis and Dtjnamene. Stebbing's statement is included, 

 I take it, in his diagnosis to indicate a point of difference between Euvallentinia and 

 Paracerceis, the genus to which Hansen had suggested that G. darioinii was most 

 closely related. In the latter genus, the metamorphosis of the mouth-parts in the 

 egg-bearing female is very complete, and includes a fusion of the mandible with the 

 head. Stebbing had only one specimen at his command, and that appears from his 

 remarks to have been a female. He gives no information on the state of its maturity, 

 and no further information on the mouth-parts except to state that they are " much as 

 in Cymodoce." 



In the material I have examined there are two adult males, one immature male 

 and three adult females, which I refer with some confidence to the Cymodoce dai'winii 

 of Cunningham. The three females have three pairs of well-developed marsupial 

 lamellae, which overlap in the median line, but none of them has eggs in the 

 marsupium. Two of the females, however, are carrying eggs in internal pouches, 

 though I have not been able to make out the number of these pouches or the position 

 of their external openings. I have carefully compared the mouth-parts of one of these 

 egg-bearing females with those of an adult male and can discern no difference 

 whatsoever. 



In C. darwinii, therefore, the mouth-parts of the egg-bearing female are not 



