Dr. H. Burmeister on two Species of Balsenoptera. 413 



Several examples were found in tlie Ceylon collection re- 

 ceived from Mr. Tliwaites. 



EXPLANATION OF PLATE XXIL 



Fig. 1. Nyctalops crassicaudata : a, profile, greatly enlarged ; h, cephalo- 

 tliorax, abdomen, and falces, upperside, with legs truncated and 

 palpi absent ; c, underside, showing maxillae and sternum ; legs 

 and palpi truncated; f/, first two joints of right palpus, from 

 outer side in front ; e, hinder extremity of abdomen, showing 

 caudal appendage, from underside ; f, profile of fore part of 

 cephalothorax, showing falx and fang ; maxilla and portion of 

 first joint of palpus truncated; g, natural length, exclusive of 

 caudal appendage. 



Fig. 2. Nyctalops tenuicaudata : «, left palpus, from outer side ; h, hinder 

 extremity of abdomen, showing caudal appendage ; c, left leg of 

 fourth pair, from the outer side; f/, first two joints of right 

 palpus, from outer side, rather in front ; e, natural length, ex- 

 clusive of caudal appendage. 



LIX. — On Balsenoptera patachonica ayid B. intermedia. 

 By Dr. H. Burmeister*. 



An interesting acquisition is the skeleton of the whale met 

 with in our river near the mouth of the Rio de Jujan during 

 the month of August. Unfortunately the skeleton is not 

 complete, owing to the negligence of the people who cleaned 

 it provisionally ; it wants the extreme point of the tail and the 

 ends of both fins, which defect greatly diminishes its scientific 

 value. 



The skeleton belongs to the species which I have de- 

 scribed (Proc. Zool. Soc. 1865, p. 191) under the name of 

 Balcenoptera patachonica^ and completes our knowledge of that 

 species, founded on an imperfect specimen, which showed some 

 characters of importance — and proves, by its perfect identity 

 with that specimen, that the other whale received last year (see 

 Boletin, p. vii) does not belong to the same species, but is 

 quite different, as I can now confidently prove by comparison 

 of the two entire skeletons. 



The whale now found was, according to the information 

 given by the sailors, 22 varas or 58 feet in length ; but as I 

 did not see the animal before the body had been dried, I cannot 

 accurately describe its external appearance. Therefore the only 

 subject for comparison is the skeleton, the general characters of 

 which I will now give. 



The specimen in question was, like the other, rather young — 

 as is proved by the vertebree separate from the free apophyses, 



* Translated by Miss Miers from the ' Boletin del Museo publico de 

 Buenos Aires,' 1871, from a corrected copy with additions sent by the 

 author. 



