OCULAR AND GENITAL PLATES. 139 



have the typical character of oculars I, V insert. In 0.9%, ocular I only is insert, and in 

 2.6 % oculars I, V, IV are insert; one specimen, 0.1 %, has I, V, IV, II insert. It is interest- 

 ing to see how regularly this rare progressive variant crops out in almost every large series. 

 The aberrant variants are few, eight specimens, or 0.8 %. Of these, two have V, IV, and 

 six I, V, 11 insert. In the percentage of typical arrangement also of arrested, progressive, 

 and aberrant variants, the Puget Sound specimens are extremely close to those from York, 

 Maine, but are slightly more progressive. In this lot there are ten specimens, 1 %, which are 

 light cream color, similar to the color commonly seen in Echinus acutus or affmis. This peculiar 

 color was also seen in specimens from St. Pierre, Newfoundland, as noted, but from no other 

 locality. It is interesting to see how closely one can correlate not only the typical character 

 but also the relative frequence of variations in specimens collected at such widely distant 

 localities. 



From Massachusetts Bay, mostly in tide pools at Nahant, a series of 588 specimens was 

 examined. Of these, 1.4 % have ocular I only insert; 95 % have I, V; and 2.2 % have oculars 

 I, V, IV insert. One specimen (text-fig. 139a, p. 132) has oculars I, V, IV, II insert, the 

 extreme progressive variant of the species. The aberrant variants, 1.5 %, are one specimen 

 with oculars I, IV insert; one with V, IV; and seven with I, V, II insert. This is an unusually 

 large proportion of I, V, II for a locality where I, V, IV is at all common. 



Through the kindness of Mr. Dwight Blaney of Boston, and from my own collecting, a 

 series of specimens was obtained from Frenchman's Bay, Maine. They were all from shallow 

 water, and varied from small to large, though none was very young. Of this series (4,000 

 specimens) one, 0.03%, has all oculars exsert, an extreme and very rare arrested variant (text- 

 fig. 135, p. 132). It is the only one found in the species except as it occurs in a very early 

 stage as a developing character. In 1.9 % ocular I only is insert; in 94% oculars I, V; and 

 in 3.3% oculars I, V, IV are insert. In two specimens, or 0.05% oculars I, V, IV, II are 

 insert. This shows a distinct gain in progressive variants over those previously considered. 

 In several of the following series there are no cases of I, V, IV, II insert, but this is so 

 rare a character, that it cannot be expected in small series. In large series it appears, how- 

 ever, with marked regularity as shown in the table. The aberrant variants of Frenchman's 

 Bay are 47 specimens, or 1 %. They are in detail, one specimen with ocular II only insert, a 

 very rare variant; eight have oculars I, IV insert; four have I, II; five V, II; and twenty- 

 nine have I, V, II insert. 



From Harpswell, Maine, through the kindness of Dr. F. D. Lambert, of Tufts College, 

 I have 300 specimens. They are all large individuals. Of arrested variants, 2.7 % have 

 ocular I only insert, one has V only, 92 % have I, V, and 3.7 % I, V, IV insert. The aberrants 

 are 1 %. Of these' two specimens have oculars V, II insert and one I, V, II insert. 



Through the kindness of Mr. J. Henry Blake, specimens were obtained from Truro, Massa- 



