S. I. /Smith — Early Stages of Ilippa talpoida. 3;j5 



oarapax about 7'""' in length, from Egmont Key, Florida. In tliis 

 specimen, the appendages ni)on the second segment are very small 

 and slender, al)out 'S'""' i<>ng, unbranched, and composed of three 

 segments — as in the adult female (Plate XLYIII, fig. 16) — of which 

 the terminal one is very short and tipped with a sparsely plumose 

 seta, similar to a single other seta upon the side of the proximal 

 segment ; there are no other setaB or hairs discoverable. The append- 

 ages of the third segment are similar, but still smaller, being scarcely 

 .-mm long, and composed of two segments only ; although the newly 

 formed appendages, as seen through the integument, show indication 

 of division into three segments. No appendages whatever were 

 discoverable upon the fourth segment. As the specimen was about 

 to molt, there is a mere possibility that there may have been very 

 rudimentary appendages upon this segment. In the adult female 

 there are three pairs of unbranched appendages, composed of three 

 segments each, and borne upon the second, third, and fourth seg- 

 ments ; no appendages w^hatever being borne upon the fifth segment. 

 In matui-e specimens of ordinary size (in which the carapax is about 

 20""" long), the appendages of the second segment (Plate XL VIII, 

 fig. 16) are about 10"'"' long; those upon the fourth, about 3-5""", 

 while those upon the third are intermediate between the two other 

 pairs. Though these observations are by no means conclusive or 

 satisi'actory, it seems probable that the egg-bearing appendages of 

 the adult Jllppa are special developments, and not metamorphosed 

 from the swimming legs of the megalops-stage. 



The following table gives, in millimeters, the results of measure- 

 ments, of the megalops and later stages, side by side for comparison. 

 The measurements in the second column are from one of the three 

 specimens, previously referred to, from Fire Island Beach, Long- 

 Island ; the others are from specimens from Vineyard Sound. 



Megalops. Fire I. M;ile. Male. Female. Female. 



Length of carapax, 3-2 4-3 8-3 14-0 13-0 20-6 



Breadth of " 2-0 2-8 6-2 10-5 9'0 15-4 



Length of abdomen, 3-0 4-5 9-0 16-0 14-5 25-0 



" ocular peduncle, 6 -7 2-4 38 36 4-G 



Diameter of ocular peduncle at tip, '3 '25 '4 '5 -5 -6 



Length of antennula, I'O I'S 3-8 5-6 5-4 7-0 



antenna, 3-4 4-8 lO'O 19-0 16-0 25-0 



" ultimate segment of anterior legs,' "8 \'i 3'0 4-1 3-8 5-8 

 " peduncle of appendage of sixth 



segment of abdomen, -65 TO 2-0 3-0 2-8 4-6 



lamella of the same, '65 1-0 2'0 2-9 2-8 4'5 



telsou, 1-7 2-5 5-3 92 8-5 14-() 



Breadth of " ' - 9 1-3 2-4 4-0 3-9 7-0 



Trans. Conn. Acad., Vol. III. 43 May, 1877. 



