Miscellaneous. 399 
On Psalidostoma, a new Genus of Fishes of 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 Psauipostoma, Kner. 
Corpus elongatum (Hsociforme) ; caput depressum, subacutum, 
oris rictus amplus; ossa supra- et infra-maxillaria forcipis ad instar 
mobilia (in Hemiramphi 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 4 corporis 
longitudinem et pinna ventralis inchoans ; pinna adiposa supra pinnze 
analis finem sita. Caput nudum ; squamee trunci ctenoides, linea la- 
teralis continua ; radii branchiostegi 4; pseudobranchie nulle. 
Of the only known species two capi measuring 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. 
Di 16, APS; V9, Fe 1496219 
Capitis longitudo 1, corporis altitudo 4 longitudinis totalis partem 
constituens ; 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 Raia Batis. By Jerrries 
Wyman, M.D., Hersey Prof. Anat. in Harvard College. 
These investigations by Dr. Wyman were made on a series of eggs 
collected in the spring of 1851 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 ovi- 
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- 
shaped 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 of 
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 permanently open. 
(5.) There are no temporary branchial fringes or filaments on the 
