1899.] NATURAL SCIENCES OF PHILADELPHIA. 333 



20. Potamalosa notacantlioides (Steindachner). 



C'lupea (Alosa) iiotacanthoides Stein., Ichthy. Notizen, ix, 20, PL 

 vii, (good). 



Local name, Machete. 



This species is very closely related to Potamalosa (Clupea) nota- 

 canthm (Giinther)," from Valparaiso, with which it may be identical. 

 The type locality of Steindachner' s species was given erroneously 

 as Mazatlan, but the specimen doubtless came from further down 

 the coast. The principal differences that separate the two species 

 lie in the scales, which are striate and fimbriate in notacanthoides, 

 and in the veinules of the opercle which are very prominent in 

 that species. Dr. Boulenger very kindly examined the types of 

 C'lupea notacanthm for us. He says: " The scales, about 48 in 

 lat. line, show no trace of striations and the opercle is not 

 veined. The dorsal scutes number 23 and 27 respectively. No 

 traces of dark spots." It is worthy of note, however, that Giin- 

 ther's types are all small, 4 inches, and it may be that the differ- 

 ence in size and age is accountable for the differences noted above. 

 We have examined specimens of P. notacanthoides from Valpa- 

 raiso, and find that they agree with those from Callao in every 

 particular. 



The diagnosis of the genus Potamalosa,' which was created to 

 receive the s])ecies P. aatlqua Ogilby ( Clapea nomehollandm Giin- 

 ther, not Meletta novcehollandke Valenciennes) will have to be 

 somewhat modified to admit P. notacanthoides. The constant 

 characters that appear to be of generic value are the position of 

 the dorsal, which originates well in advance of the middle of the 

 body, the number of branchiostegals and the rays of the anal.'' 



Five specimens, 1. 200-240 mm. 



Head 3-3i; depth 3; eye 4^5; pectoral 14 in head (as in Stein- 

 dachner' s figure, 2f in his description). There is considerable 



' Giinther. Cat. Fishes Brit. Mus., vii, 443, 1868. 



^Ogiiby, Proc. Linn. See. N. S. Wales, xxi, 1896, 504 (1897). Ibid., 

 I.e., 1897, Pt. i, Apr. 28, p. 70. 



* The following synopiis will show the differences between the two species 

 of the genus : 



Gen. Potamalosa Ogilby. Origin of dorsal well in advance of middle of 

 body ; branchiostegals 8 or 9 ; anal rays 18 or less, — 



(a) Dorsal scutes feeble ; scales peciinate and striate ; muciferous system 

 highly developed ; opercle veined notacanthoides. 



(b) Dorsal scutes prominent ; sealer entire ; muciferous system confined 

 to main arteries ; opercle quite smooih anitqua. 



