NATURAL SCIENCES OP PHILADELPHIA. 213 



August 6. 

 The President, Dr. Ruschenberger, in the chair. 

 Nine members present. 



Note on Coitus Grainlandicus, Fabr.Bv. Gill communicated 

 the results of certain observations made on Cottus groenlandious, 

 *ab. (Acanthocottnsgrcenlandicus, Girard), during the past season 

 at the island of Grand Manan, New Brunswick. 



Two forms, agreeing in most respects except color, have been 

 always noticed together by those who have been in a position to 

 observe numbers. The most obvious external difference between 

 these consists in the color, one having the flanks downward and 

 the abdomen yellowish, while in the other form the abdomen is 

 spotted with white. Descriptions in several works have been 

 based on only one of these forms, but in Giinther's Catalogue of 

 the Acaiithopterygian Fishes" (II. p. 161), under the general 

 term Cottus grcenlandicus" the two forms are mentioned, one 

 being T ar. a. Sides of the belly with large white spots ;" the 

 other M ar. p. Sides irregularly marbled ;" each was represented 

 in the British Museum by four specimens. No suspicion of any 

 sexual relation of those forms was expressed. 



The universal occurrence of these two forms together and in 

 approximately equal numbers led the speaker to suspect that 

 they really represented sexual conditions of the same species 

 Dissection confirmed the suspicion, and it was found that all in- 

 dividuals with white spots on the abdomen were males, and all 

 without, females. In order to remove doubt, sixteen specimens 

 were dissected, all caught within a couple of hours, at Grand 

 Manan, from the wharf of Mr. Walter McLaughlin. 



Six of these had (1) the belly ornamented with very distinct 

 white round spots, and (2) the ventral fins were white, banded 

 with black ; all these were furnished with spermaries ; (3) the 

 spiny tubercles on the sides were also more numerous, and de- 

 veloped (below as well as above) the lateral line; (4) the spinous 

 dorsal fin was appreciable higher, and (5) several of the median 

 rays (sixth to eleventh) of the pectoral fins were muricated or 

 studded with minute tubercles. 



Of the other form, ten specimens were examined and found 

 with well-developed ovaries (the right larger than the left). These 

 were (1) yellowish towards the belly, and with (2) the ventrals 

 yellow, banded with black; (3) the spiny tubercles were, as a 

 rule, less developed, and in one specimen sparsely (2-4) existent 

 below the lateral line ; (4) the spinous dorsal was comparatively 

 lower, and (o) all the pectoral rays were perfectly smooth on their 

 inner surfaces. 



The intestinal canal from the caeca to the anus, when extended 

 was about twice as long as the entire fish (including the caudal)! 



