''°i89l"''] PROCEEDINGS (JF THE NATIONAL MUSEUM. 283 



the biul) upon every fourth one up to aud includiiif,' the twenty-fifth, 

 then upon every fifth one up to and includini;- the forty-first, after which 

 the exceptions l>ocotne so numerous that no rule is evident. 



The examination of so many cases shows a (h'finite tendency to lim- 

 itation in the bands to certain somites in the anteiior region and a 

 greater and greater irregularity in the posterior region. Tiie oldest 

 region in each individual of the two concerned in budding is remarka- 

 bly constant in respect to the coloration. Thus in the one hundred aud 

 ten cases studied the nurse or anterior thirteen somites presented ab- 

 normal bands as follows : On the fifth somite a band in only eleven cases; 

 on the seventh none at all ; on tiienintii in only four cases; on the elev- 

 enth in only six cases; on the thirteenth in only five cases. On the fourth 

 somite the normal band was wanting in four cases, never on the third 

 somite. The rule of banding in the bud is not as strictly adhered to as 

 in the above nurse. Thus bands occur abnormally upon the fourteenth 

 somite in fifteen cases, are wanting upon the fifteenth in thirteen cases, 

 occur upon the sixteenth in eight cases, upon the seventeenth in twenty 

 cases, are wanting upon the eighteenth in twenty cases, and soon. 



These facts seem sufiicient to indicate that we have in this S.\lli<l a 

 marked tendency to the acquirement of a regular metanieric marking, 

 which, however, does not coincide with the metamerision of the somites 

 but tends to follow a special law, best expressed in the oldest part of 

 the body in which certain alternating colored aud not colored som- 

 ites are distinguishable — a series of groups or combinations of somites 

 thus following one another. 



In one case, a nonsexual individual with well-advanced bud, the pos- 

 terior zoijid was inverted Y shaped, being provided with two complete 

 but not quite identical posterior e-nds ; au abnormality previously 

 noticed in various xVnnelids by many observers, but in this case striking 

 from the length of the divided region and the activity of these two 

 parts in the crawling movements of the whole. 



Proceiaea oruata Mar. and JJohy. 



Makion and Bobretzky. Anuel. du Golfe do Marseille > Ann. Sci. Nat., 6th scr., vol. 

 2, pp. 44-4(5, PI. V, Fig. 14. 



Taken in large numbers near Moorhead City on sponge, in June. 



Proceraea rubropunctata Langerhans. 



Langkrhans. Dio Wurinfanua von Madeira. > Zeit. f. wiss. Zool., vol. '23, pp. 579, 

 0^0, IM. XXXII, Fig. 30. 



This species also occurs in abundance. 



