192 MEMOIRS OP THE CARNEGIE MUSEUM. 



the caudal region of the body), and Series 5 (surface injury to the dorsal region), 

 did not i^rove fatal during the first twenty-four hours. On the contrary, the 

 fishes of these series either were not visibly inconvenienced by the injuries, or, as far 

 as could be observed, were completely recovered from the shock of the operation 

 by the end of the first day. Comparing these series with the collections: the 

 majority of mutilated specimens regenerating injuries were of the type of Series 

 1 or 2. Not a single individual showing an injury similar to that inflicted in Series 5 

 was taken. The absence of specimens with an injury of the same tji^e as that 

 inflicted in Series 5, namely, a non-fatal injury in the dorsal quarter, as has already 

 been discussed, may be due to the fact that the dorsal quarter is less liable to 

 injury than the caudal half. 



Nature of Regenerations. — Regenerations were found of various degrees of 

 completeness, in some case almost the entire part removed appeared to have been 

 restored. Caudal appendage, anal fin, muscle tissue, skin, and scales were all 

 regenerated. Three cases, one for each species, will suffice to show the nature of 

 these regenerations. 



A specimen of Eigenmannia macrops from Rockstone, estimated length one 

 hundred and sixty-five millimeters by comparison with uninjured specimens of 

 the same species, had lost the entire caudal appendage, about sixty-five millimeters 

 in length, and some thirty-five miUimeters of the caudal portion of the body. 

 The regenerated piece was eighty miUimeters in length, fifty millimeters being 

 caudal appendage, and thirty millimeters body proper. The ventral edge of the 

 thirty millimeters of body-tissue bore a well formed anal fin of normal width. 

 It was perfectly fused with the old anal at the line of injury. The regenerated 

 tail was much narrower both dorso-ventrally and laterally, giving the fish a pinched 

 or constricted appearance at the line of injury. Plate XXI, fig. 1, shows a normal 

 uninjured specimen of this species, and Fig. 2 of the same Plate represents the 

 specimen described in the preceding lines. 



A specimen of Eigenmannia virescens of one hundred and eighty-five millimeters 

 in length, from Wismar, is chosen to illustrate this species. In this specimen the 

 regeneration is especiaUy complete. The regenerated part is quite normal in size, 

 length, color, and markings. It differs from the uninjured portion of the fish in 

 but two particulars: (1) it was a little thinner; (2) it did not fit quite perfectly on 

 the ventral edge where it joined the old anal fin. The part regenerated was sixty- 

 eight millimeters long, of which thirty-eight millimeters was caudal appendage and 

 thirty miUimeters body proper. This seemed by comparison with other normal 

 specimens to be about the amount that had been removed. The breadth at the 

 base was two and one-half millimeters, as compared with the three and one-half 

 miUimeters of uninjured tissue in a normal specimen, and the depth six millimeters; 

 that of the old tissue being eight millimeters. (See Plate XXI, fig. 3.) 



One of the largest specimens of Sternopygus macrurus, from Georgetown 

 Trenches, five hundred millimeters long, showed three distinct injuries: (1) on the 



