938 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [12] 



tral proboscis, around which is a zone in which are placed the sexual 

 bodies {oa.). Outside of this zone is a third zone, the inner coronal 

 muscle {ynus. cor. i), on the periphery of which is the external coronal 

 muscle {mtis. cor. e.). The very periphery is made up of the under surfaces 

 of the socles of the sense-bodies and marginal lappets {mg. Ip.). 



Outside (abaxially) of the musculus coronalis externus {mus. cor. e.) 

 the lower surface of the twenty-two socles of the sense-bodies [soc. sb.) 

 and the subumbral surface of the marginar lap])ets show nothing pecu- 

 liar. The socles of the sense-bodies {soc. sb.) have, however, a small, 

 medial, radial groove, more or less reddish in color, which extends from 

 the sense-body to the edge of the coronal muscle radially along its 

 medial line. 



The musculus coronalis externus {mus. cor. e.) is a very powerful ring- 

 shaped muscle of light-brown color, not visibly marked into regions, and 

 opa(iue. Width, S-""^. 



Axially to the external coronal muscle there is a musculus coronalis 

 internus' (wtws. cor. i.), a thin, transj^arent muscle, through which can 

 be seen twenty-two pairs of radial clas])s {cL), which bind it to the lower 

 surface of the umbrella, separating chymiferous pouches, which extend 

 radially from a coronal "intestine" yet to be described. Each pair of 

 clasps correspond with a radius which passes through a sense body. 



Between the inner edge of the internal coronal muscle and the line of 

 attachment of the proboscis is a zone 10'""' wide, in which lies the kidney- 

 sha{)e(l sexual organs {oa.). The lower wall of this region is muscular 

 and membranous, formed of longitudinal and radial fibers, which in 

 eight radii become radially concentrated and ibrm the deltoid mufs(;les 

 {mus. delt.), which separate the sexual glands from each other. The 

 width of these muscles varies, but 1 do not find the regularity of this 

 variation as marked in our species of Atolla, as Hseckel describes it to 

 be in A. Wyvillii. In the two sexual bodies which I have figured {oa.), 

 the deltoid muscle which separates them is narrower than that {mns. 

 (kit.) which separates the pair from an adjacent pair. The lower wall of 

 the zone in which the genitalia lie covers the sexual glands {oa.), so that 

 these bodies lie in a circular sinus, which is shown in one of the intervals 

 which has been cut into between two glands. (See interv^al between 

 upper ovary {oa., PI. II) and that at left.) Each sexual body is bean- 

 shaped, inflated with ova, with hilum axially placed. Diameters, 12"'"' 

 and 10™^". Color, chestnut brown. The internal zone of the subumbrella 

 is occupied by a bag-shaped structure with dark blue or purj)le walls, 

 which form the stomach or proboscis. The walls of this structure are 

 formed of eight sections of two sizes. The four perradial sections {lb. 

 per.) are broad and bag-shaped (25™"' in breadth), tapering from inser- 

 tion to the edge of the open mouth {or.). The interradial {lb. inf.) sec 

 tions, which alternate with these, are narrower (5™"' wide), likewise taper- 

 ing, and fused with the walls of the subumbrella. The bag-shaped 

 structure or j)roboscis formed by the combination of these sections is 



