192 MEMOIRS OF THE CARNEGIE MUSEUM. 
the caudal region of the body), and Series 5 (surface injury to the dorsal region), 
did not prove 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 
lor2. Not asingle individual showing an injury similar to that inflicted in Series 5 
was taken. The absence of specimens with an injury of the same type 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 lable 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 Higenmannia 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 millimeters of the caudal portion of the body. 
The regenerated piece was eighty millimeters 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 X XI, 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 Higenmannia virescens of one hundred and eighty-five millimeters 
in length, from Wismar, is chosen to illustrate this species. In this specimen the 
regeneration is especially 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 millimeters 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 
millimeters of uninjured tissue in a normal specimen, and the depth six millimeters; 
that of the old tissue being eight millimeters. (See Plate X XI, fig. 3.) 
One of the largest specimens of Sternopygus macrurus, from Georgetown 
Trenches, five hundred millimeters long, showed three distinct injuries: (1) on the 
