14 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 21 



of the first pleopod of the male is based on that employed by Gordon 

 (1937, pp. 152, 154) and refers to the position of the pleopod in situ, 

 i. e., before it is removed for examination and figuring. The concave 

 surface that lies against the thoracic sternal segments is called the sternal 

 surface, a figure showing which is said to be drawn from the sternal 

 aspect. The opposite side, lying against the abdomen, is referred to as 

 the abdominal surface." Tweedie recognizes in Sesarma an outer and an 

 inner abdominal facet, the former lying against the inner surface of the 

 abdominal segments, the latter against the hinder part of the alimentary 

 canal. For the sake of uniformity he uses the right pleopod, which for 

 Sesarma is figured resting on the outer abdominal facet. 



It was convenience, rather than a desire for uniformity, that led the 

 writer to adopt essentially the same system. The procedure followed is 

 to place the specimen ventral side up in the dissecting tray with its head 

 toward the observer. The abdomen is then lifted with forceps held in 

 the left hand, while the first pleopod is teased out with a dissecting needle 

 held in the right hand. It is thus the right pleopod that is under the 

 worker's right hand, and the sternal aspect that is exposed as it is lifted 

 and tilted backward. In examining large numbers of specimens the 

 pleopod need not be removed ; merely allowing the abdomen to fall back 

 into its accustomed place will often serve to hold the reverted pleopod 

 in a position suitable for study. 



After drawings of the entire first pleopod throughout the subfamily 

 Inachinae had been made, it was found that most of the significant 

 differences occurred in the terminal portion. The first drawings were 

 therefore discarded in favor of a more detailed set, and only the terminal 

 portion was figured for the remaining subfamilies. It was similarly found 

 that the male second pleopod, a minute structure in the Majidae, pre- 

 sented no characters of taxonomic value, although its size and diversity 

 among the Parthenopidae require that in that family it receive consider- 

 ation along with the first. 



Summary of Additions and Changes 



The subfamily Oregoniinae is proposed to receive the genus Oregonia 

 (ex Inachinae) and the genera Hyas and Chionoecetes (ex Pisinae). 



The genus Paradasygyius is proposed to receive Dasygyius depressus 

 (Bell) and its Atlantic cognate, D. tuberculatus Lemos de Castro 

 (1949). The genus Epialtoides is proposed to receive those species of 

 Epialtus, sensu lato, having five, rather than six, free male abdominal 

 segments. 



