628 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvii. 



The account also includes a partial description of the eggs and larva\ 

 and it is unfortunate that the manuscript name could not have been 

 given to the species, since this description so far iuitedates that of the 

 author. 



In the present account acknowledgment has been made of such facts 

 as have been taken from Dr. Gurley's manuscript. 



At present this species has been found only upon the dog-fish. Am la 

 calva. Professor Reighard writes that it is found over the outside of 

 the fish generally, the larger number on the anterior part of the body 

 and the head. Init some on the tins. The}^ are most numerous on the 

 ventral side of the body in front of the pelvic fins. They are never 

 found on the gills or anywhere else internally. They are not notice- 

 able until the fish have been for some time in the aquarium. 



This is one of the largest of the American fresh-water species and 

 is the best of any the author has seen for purposes of study, since it is 

 particularly transparent when alive and also when cleared in clove oil. 

 There is no difficulty in making out all the details of the internal 

 anatomy even to the nervous system and its connections. 



It is pale brownish white in color, sparsely covered on the dorsal 

 and A'entral surfaces with small pigment spots of a reddish hue. In 

 all the living specimens seen by the author there were eight faint red- 

 dish bars running transA^ersely across the dorsal surface. Gurley, 

 however, sa3\s: 



The ground color is faint grayish or grayisli green. The nio.st conspicuous mark- 

 ings are the rose to purphsh red bars, which are most distinct marginally where they 

 form well-defined spots. 



Probably the color as well as the distinctness of the bars varies con- 

 siderably in difierent lots of individuals. 



The dorsal surface of the ovary and semen receptacles in the female 

 and the abdomen of the male in the vicinit}- of the testes are heavil}'^ 

 pigmented with circular spots of a rich dark brown. The structural 

 details are as follows: 



General form. — Dorsal surfaci\ — The carapace is obovate and 

 fully as wide as and often wider than long; the antero-lateral sinuses 

 are distinct, leaving a well-defined frontal lobe which, however, does 

 not project yqvj far, since it is flattened anteriorly. The posterior 

 sinus is narrow and about one-third the entire length of the carapace, 

 and is squarely truncated at its base. Its sides converge rapidly in 

 passing backward so that the broadly rounded lobes of the carapace 

 overlap considerably at their tips (fig. 1). 



The sutures dividing the carapace into its respective areas are char- 

 acteristicalh^ arranged. The two central longitudinal ribs {r) are fairly 

 close togethei" for such a broad carapace and are almost parallel except 

 at their anterior ends. The horseshoe suture {hs.) separating the 

 cephalic from the other areas is comparatively short and narrow. 



