668 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. XXVII. 



Family ASELLID^E. 



ASELLUS TOMALENSIS Harford. 



Asellns tomalemis Harford, Proc. Cal. Acad. Sei., VII, 1877, pp. 54-55. 



The description of this form is given in tlie following concise 

 manner: 



Head a little transverse, narrower than the body. Upper antenna not reaching 

 to the extremity of the peduncle of the lower. Flagelluni of lower antenna longer 

 than its peduncle. Body narrow in front, gradually increasing in width toward the 

 tail. 



Peduncle of caudal appendages more than half the length of the terminal filaments. 

 Length six-twentieths inch. 



The description is from a single specimen. 



Eight specimens of a species of Asellus were collected by the Ilarri- 



man Alaska expedition at Lake Washing- 

 ton, Seattle. I have referred them to the 

 above species, being unwilling to describe 

 a new species of Asellus from a locality 

 so close to that from which A. tomalensis 

 was found (Tomales Bay, California), 

 when so little is known about A. t<nimlen- 

 sls. Some of the specimens were sent to 

 Dr. William E. Ritter for comparison 

 with the type and only specimen of A. 

 toinalensls in the collection of the Cali- 

 fornia Academy of Sciences. The result 

 of his comparison is given in the follow- 

 ing quotation from his letter: 



About the only difference that I am able to 

 make out is in the fact that the inner ramus of the 

 sixth pleopods (uropods?) of A. tomalensis is about 

 half as long as the exopodite and that neither is 

 armed with a tuft of hairs at the tip. This is the 

 case with the one appendage present, but its mate 

 is gone. It is possible that the hair tuft may have 

 been broken off, but the tips of the rami them- 

 selves are ])erfectly smooth. They show no evi- 

 The fact, however, that the general hairiness of 

 the Academy specimen is about the same as that of your specimen makes me sus- 

 picious that the tuft referred to has been removed. The antennie and antennules 

 differ in no essential respect so far as I can see. The chelipeds of the type specimen 

 I am unfortunately unable to find. 



Description of specimens. — Body narrow, elongate, gradually widen- 

 ing somewhat from the anterior to the posterior extremity. 



Head but little narrower than the first thoracic segment and about 

 twice as wide as long; frontal margin slightly excavate and without 



Fig. 15. — Asellus tomalensis Har- 

 ford. X 9. 



dence of having lost anything. 



