Vol. L April, 1926 No. 4 



BIOLOGICAL BULLETIN 



SPERMATOGENESIS OF THE BLACK-CLAWED 



CRAB, LOPHOPANOPEUS BELLUS 



(STIMPSON) RATHBUN. 



NATHAN FASTEN, 



DEPARTMENT OF ZOOLOGY, OREGON AGRICULTURAL COLLEGE, 

 CORVALLIS, OREGON. 



INTRODUCTION. 



During the past few years I have been studying various 

 cytological aspects of the gonads of numerous Pacific coast 

 Brachyura (Fasten, '17, '18, '21 and '24) giving particular 

 attention to the problem of spermatogenesis. The present paper 

 is a continuation of the above research, dealing with the matu- 

 ration of the male gametes of the black-clawed crab, Lopho- 

 panopeus belhis (Stimpson) Rathbun. This Brachyuran is a 

 native of the Pacific coast of the United States, and according to 

 Schmitt ('21), it ranges from Alaska to southern California. 

 The material upon which the present contribution is based was 

 obtained mainly along the shores of Puget Sound. In certain 

 localities of this region, particularly in the San Juan islands, 

 the black-clawed crab is found to be quite abundant. 



MATERIAL AND METHODS. 



The material used consisted of smear preparations of the 

 testis of the crustacean under consideration. Although sectioned 

 material was available, nevertheless the smears were found to be 

 so superior that all of the stages and drawings were derived from 

 them. The time for obtaining the best material was the latter 

 part of June and the first portion of July. These periods agree 

 quite well with what has been found to be the case in the testes 

 of other Brachyura. 



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