142 PROF. W. M. SMALLWOOD ON HYDROID3 [Jan. 18, 



body in several (six) more or less distinct groups. On the left 

 side, lateral to the rhinophore, there are in the first group nine 

 very small branchiae. These are followed without any noticeable 

 interval by twenty-one branchiae of larger and uniform size. 

 These all arise from near the edge of the dorsum, but bend over 

 so as to give the appearance of growing out of the middle as well. 

 In the third group of the left side there are twenty-two branchiae, 

 part of which grow out of the middle of the back. Then follows 

 a free space about equal to the area occupied by the third group ; 

 next comes the fourth group with fifteen branchiae, several of 

 which are small. A few of these likewise arise from the middle 

 of the back. Between the fourth and fifth groups there are two 

 small branchiae close to the foot (not shown in the figure). In 

 the fifth group, nine were counted. The rest of the dorsum and 

 side of the body has fifteen ; these extend quite to the tip of the 

 tail and entirely cover the body in this region. On the right 

 side of the body, taking the branchiae in the same order as on 

 the left, first, there are nine small ones followed immediately by 

 twenty-five : in the next (third) group twenty-four, then (fourth) 

 thirteen, (fifth) eleven, and in the final group twenty-four. 



Text-fig. 9. 



Facelina agari, sp. n. 

 Viewed from the left side. Magnified 2 diameters. 



Between the fourth and fifth groups on the right side there was 

 one small branchia. These enumerations show that the total 

 numbers (90 and 107) on the two sides of the body are not the 

 same, and that the corresponding groups may differ widely in 

 number. The branchiae have an oscillating movement, which is 

 quite regular when the animal is undisturbed. 



The colour of the body is light chocolate. There are a few 

 splotches of this colour on the dorsal -anterior portion of the foot. 

 The portion of the body free from the branchiae looks to the un- 

 aided eye as if there were numerous minute white spots all over 

 it. Under the microscope, on a black background, these spots 

 are seen to consist of from one to many white spherules grouped 

 in a variety of odd shapes. These white spots thus viewed are so 

 prominent on the light chocolate background, that they appear to 

 be minute roughened areas ; they do not, however, project beyond 

 the surface. The branchiae, especially those nearest the dorsal line, 

 have a slight bluish colour around the base. Each branchia has 

 a ground-colour of light chocolate with many white splotches 

 irregularly disposed. The Avhite splotches are many times larger 

 than those on the dorsum. The tentacles have similar white 

 splotches, but they are more numerous. The rhinophores are 



