LAGENORHYNCHUS THICOLEA. 89 



wards relegated it to the section Electra, which he raised to generic 

 rank. Professor Flower, in his recent admirable essay, seems first in 

 doubt as to whether it should not be assigned to Lagenorliijnchus (P. Z. 

 S., 1883, p. 490), but later describes it in connection with the genus 

 rrodclphinus, and finally places it in his tentativ^e list of species of 

 that genus (P. Z. S., 1883, pp. 49G and 512) near P. ohscurvs. 



Tbe considerations which lead me to assign this species to Lagenorhyn- 

 chits are the same which influenced me in the case of L. loncjideMa (p. 99), 

 to which in fact the present species appears to be closely related. It 

 differs from that species in that the beak is shorter and narrower, the 

 intermaxilliiries narrower, the temporal fossae smaller and more oval. 

 But it diflers also especially from L. longidens, and indeed from all other 

 species to which it can be approximated, in having about 42 teeth in 

 each ramus of the mandible. The teeth in the upper jaw would appear 

 to be 45-45, but their number can only be estimated on account of the 

 imperfect condition of the skull. 



The label states that this skull was derived from the west coast of 

 iSTorth America, and was taken out of Dr. Dickie's collection. If the 

 record is correct, it is somewhat singular that the species was not met 

 with by Captain Scammou or Mr. Dall. There are no specimens in the 

 national collection which can be assigned to it. 



LAGENORHYNCHUS BREVICEPS Wagner. 



A skull of this species is figured by Messrs. Van Beneden and Ger- 

 vais,* under the name of Lagcnorhynchns hrevieeps, but the authors do 

 not state explicitly that it is the type of Hombron and Jacquinot, fig- 

 ured in the atlas of the voyage of the Astrolabe. That the two figures 

 are not from the same specimen appears probable from the fact that the 

 latter represents an entire skull, while the former represents one from 

 which the top of the brain-case has been removed. In general appear- 

 ance the two figures though much alike are not identical. Professor 

 Flower has referred Messrs. Van Beneden and Gervais's figure to 

 Prodelphimis* Hombron and Jacquinot's figure of the exterior,t how- 

 ever, represents a dolphin having the contours and the coloration of a 

 Lagenorhynchus^ and the species must, I think, be referred to that 

 genus. Wiiether it should be regarded as identical with L. thicolea is 

 perhaps somewhat questionable, for while the skull figured in the atlas 

 of the Astrolabe expedition agrees with the type-skull of L. thicolea the 

 teeth are considerably more numerous in the latter. The original 

 specimen of I), brericeps was from the Rio de la Plata. 



It is to be observed, however, that the naturalists of the Astrolabe 

 exi)fdition state that they found only fragments of a skull, etc., in the 

 collection. It is possible, therefore, that the skull which is figured as 



*Ost^o<^rapliie <les C6t-iccs, pi. xxxvr, fig. 2. 



* Proc. Zoj)l. Soc, London, \'SS'^, ]». 4i»G. 



t Zool. Voyage Astrolabe et Zelco, atlas, pi. 22, fig. L 



