250 Prof. M'lntosh's Notes from the 



forms measuring 34 millira. The British examples are thus 

 more precocious. Professor Agassiz also describes " a last 

 row of somewhat smaller tubercles along the median line of 

 the abdomen behind the ventrals." In all probability 

 " median " should be " lateral," unless the American form 

 specifically differs. 



As the fish increases in length the second and third rows 

 extend posteriorly and by-and-by become hispid with minute 

 spines ; tlie third especially presenting large crescentic emin- 

 ences bristling with prominent spines, which, while occurring 

 over the tubercle generally, also form a pectinate ridge 

 distally. 



In June the young lumpsuckers range from less than 10 to 

 23 millim., the smaller forms being more frequent at the 

 beginning, the larger towards the end of the month. In 

 those of 23 millira. the spiny tubercles are all better marked 

 than at 19 or 20 millim. Thus, the second and third rows 

 (lateral) extend to a line passing through the middle of the 

 second dorsal and the anal. In full development each process 

 in the row forms a multispinous tubercle. A row of small 

 spinous tubercles also occurs at the lower border of the oper- 

 cular region, one extending to the branchiostegal region. At 

 this stage (23 millim.) the second dorsal has 11, tiie breast- 

 fins 21, the anal 10, and the caudal 11 rays — these numbers 

 agreeing for the most part with the full number in the adult. 

 On the other hand, the young differs from the latter in the 

 greater proportional size of the eyes, the larger proportional 

 size and nature of the third and ventral tubercles, in the shape 

 and condition of the first dorsal fin, and in the arrangement 

 of the pigment. At this, as well as the previous stage, 

 minute leeches are occasionally found on the skin. 



In July eggs were once obtained in a fully ripe condition 

 (viz. the 12th), but their deposition on the rocks would seem 

 to be rare at this period. Young postlarval forms of only 

 6*5 millim. are still found at tiie surface, e. g. of St. Andrews 

 Bay and the Forth, the majority, however, being between 

 11 and 30 millim. Many of an intermediate size are obtained 

 in rock-pools. At 30 millim. all the rows of spinous tubercles 

 are extremely prominent, the most conspicuous being four of 

 the third row. This and the second row extend almost to 

 the base of the caudal fin. Such a fish is much more rugose 

 than the adult, whose rows of flattened tubercles contrast with 

 the projecting ridges and their hispid tubercles in tlie young. 

 The first dorsal fin at this stage has a tendency to be adpressed, 

 so that its tip is guarded by the double row of s|)iuous 

 tubercles on the dorsum. Further, the flattened abdominal 



