Miscellaneous. 399 



On Psalidostoma, a new Genus of Fishes 0/ the Family Characini. 



By Professor Kner. 

 This genus is remarkable partly from the character of its dentition 

 and partly from the mobility of its jaws. In the latter respect it 

 reminds us of Hemirhamphus, Belonesox, and Panchax, and conse- 

 quently forms a transition between the Characini and the Scombere- 

 soces and Cyprinodontes ; it is upon this character that the author 

 has founded his generic name Psalidostoma (Scissors-mouth). The 

 generic characters are as follows : — 



Genus Psalidostoma, Kner. 



Corpus elongatum (Esoci/orme) ; caput depressum, subacutum, 

 oris rictus aniplus ; ossa supra- et infra-maxillaria forcipis ad instar 

 mobilia {mil emir amphi modum); ubique dentes canini validi in medio, 

 ad latera vero dentes uniseriales breves lobati ; retro hos in ambis 

 maxillis fascia mediana trigona dentium velutinorum. Pronotum 

 carinatum ; abdomen rotundatum ; pinna dorsalis retro ^ corporis 

 longitudinem et pinna ventralis inchoans ; pinna adiposa supra pinnse 

 analis finem sita. Caput nudum ; sqnamee trunci ctcnoides, linea la- 

 teralis continua ; radii branchiostegi 4 ; pseudobranchiee nullee. 



Of the only known species two examples, nrieasnring rather more 

 than seven inches in length, have been sent by Consul Binder from 

 the White Nile. The author proposes for it the name of 



Psalidostoma caudimaculatum, Kner. 

 D. 16, A. lo, V. 9, P. 14, C. 19 

 Capitis longitudo |, corporis altitudo ^ long;itudinis totalis partem 

 constitucns ; pinna caudalis lobata, fusco-nigro punctata. 

 From the White Nile. — Bericht der Acad, der Wiss. in Wien, 

 June 23, 1864, p. 110. 



Observations on the Development of llaia Batis. By Jeffries 

 Wyman, M.D., Ilerscy Prof. Anat. in Harvard College. 



These investigations by Dr. Wyman were made on a series of eggs 

 collected in the spring of 18.51 and of the three subsequent years. 

 The more important conclusions arrived at are stated as follows at 

 the close of the paper : — 



(1.) The yelk-case is formed in the glandular portion of the oti- 

 duct, and is begun previously to the detachment from the ovary of 

 the yelk which is to occupy it. 



(2.) The embryo, before assuming its adult form, is at first eel- 

 shnped and then shark-shaped. 



(3.) The embryo is for a short time connected with the yelk by 

 means of a slender umbilical cord ; the cord afterward shortens, and 

 the young skate remains in contact with the yelk until the end of 

 incubation. 



(4.) There are seven branchial fissures at first: the foremost ot 

 these is converted into the spiracle, which is the homologue of the 

 Eustachian tube and the outer ear canal ; the seventh is wholly closed 

 up, and no trace remains ; the others remain pertuanently open. 



(.5.) There are no temporary branchial fringes or filaments on the 



