64 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 21 



to Batrachonotus nicholsi, only the male bearing U.S.N.M. No. 21872 

 appears to be a counterpart of this form of female; but even here the 

 granules are beginning to be elevated on slender stalks. The remaining 

 specimens, most of which are females, have the long carapace spines and 

 the attenuated postorbital spines characteristic of Euprognatha bifida. 

 A special word is in order regarding extensive Hancock expeditions 

 material from the Gulf of California, since it is critical with respect to 

 the status of Batrachonotus nicholsi. It is only in the northern part of 

 the Gulf, which is the type locality for B. nicholsi, that one commonly 

 finds females of this form associated with males of the Euprognatha 

 bifida type. In the southern part of the Gulf, as at Cabeza Ballena, all 

 but one or two of the largest males as well as all females of a series of 

 19 individuals are of the Batrachonotus nicholsi type as well, while a 

 series of 19 specimens from an intermediate locality, Ildefonso Island, 

 are typical Euprognatha bifida in both sexes. Material from San Esteban 

 Island, station 562-36, shows a progression from typical Batrachonotus 

 nicholsi females with the granulate intestinal region to males having 

 first a single, then a cleft spine, and finally, the double intestinal spines 

 of typical Euprognatha bifida. One might with justification paraphrase 

 the paragraphs on Variations given by Rathbun (1925, p. 97) with 

 reference to the Atlantic species, Euprognatha rastellifera, substituting 

 for E. rastelliferae marthae the tuberculate form erroneously designated 

 as Batrachonotus nicholsi, and for E. rastellifera acuta the typical E. 

 bifida. As with the Atlantic species, however, emphasis should be placed 

 on the concluding sentence: "None of these forms is entirely restricted 

 to its own range, they overlap one another, and two forms may occur 

 in the same haul." 



Although the exhaustive series of Euprognatha bifida obtained by 

 Hancock expeditions shows variations equaling the imposing array of 

 material marshalled by Rathbun (1925, pp. 98-101) under E. rastelli- 

 fera, it is not proposed to burden the Pacific species with a like number 

 of subspecific names. The types already selected are not extreme, for 

 neither is typical Euprognatha bifida as spinulous, nor is typical Batra- 

 chonotus nicholsi as tuberculate as specimens which may be found. 

 Furthermore, both type localities lie within the Gulf of California, 

 whereas the species ranges from Lower California to Ecuador. Could 

 one form, the spinulous, for example, be said to predominate in the 

 north and the other, the tuberculate, in the south, occasion might be 

 taken to retain nicholsi as a subspecies. However, since both forms occur 

 throughout the range, it seems preferable to synonymize B. nicholsi 



