20 ARMANDIELLA ROBEETIAN^J. 



being bevelled from below upward and forward, and furnished with short and somewhat 

 clavate cirri, the most conspicuous being the larger ventral pair. Bristles inconspicuous 

 anteriorly, visible under the microscope at the commencement of the posterior third, 

 evident and long at the caudal process, simple, tapering, and curved. Colour of the 

 dorsum greenish with dark brownish specks, a dark central transverse bar occurs at 

 intervals, and a row of dark specks (eyes) also at intervals in the groove above each 

 ventral longitudinal muscle. Under surface pale greenish. 



Synonym. 

 .1908. Armandia Robertianse, Mcintosh. Ann. Nat. Hist., ser. 8, vol. i, p. 376. 



Habitat. — Dredged amongst sandy mud in six or seven fathoms oh° one of the small 

 islets in the sound of Harris, August, 1872. 



Head (Plate XCV, fig. 5) forming a somewhat obtuse rounded cone, marked dorsally 

 by a constriction, whilst ventrally the prominent ridges of the ventral longitudinal muscles 

 leave only a small rim at the snout free. Minute nuchal organs are present on each side 

 just in front of the termination of the lateral groove, but they are only distinct in life. 



Body (Plate XCV, fig. 5) about 14 mm. in length, somewhat short and thick, tapered 

 at each end, rounded dorsally and grooved ventrally, the powerful ventral longitudinal 

 muscles forming a conspicuous ridge on each side — almost from end to end. The mouth 

 opens as a small pit behind the isthmus of the great longitudinal muscles at the tip of the 

 snout. The colour of the dorsum is greenish, speckled with dark brownish points, a dark 

 central transverse bar occurring at intervals, so as to give the dorsum a segmented 

 appearance. Much of this pigment remains in the spirit-preparation. The ventral 

 surface is pale greenish. 



The posterior end is abruptly diminished to an upturned caudal process, which is ter- 

 minated by a slightly oblique border (the slope trending from below upward and forward) 

 furnished with short and somewhat clavate cirri, two being dorsal and two ventral, 

 besides two or three lateral, the most conspicuous pair being the ventral. These form a 

 fringe to the anal aperture which thus opens into a small funnel. The diminished caudal 

 region is marked by closely arranged circular stria3. The course of the great ventral 

 longitudinal muscles differs from that of certain species, since they stretch from end to 

 end, forming two prominent lateral ridges from the anterior border to the base of the 

 diminished caudal region, and being lost on the upturned narrow process. In the groove 

 above each ventral ridge is a series of dark brown pigment-spots (eyes) at regular 

 intervals, but no bristles are visible except in the posterior region, where five to seven 

 tufts of slender, curved, glistening bristles form a fringe on each side— sloping down- 

 ward and backward. Moreover, upon the narrow caudal process a few occur on the 

 sides distally, but their origin is uncertain. These bristles (Plate CIII, fig. 15) are trans- 

 lucent, taper to a fine point and do not show evident striations. Small tufts of these 

 occur considerably in front of those just mentioned, but are only visible under the micro- 

 scope. Whether in the living form these bristles go further forward is unknown. 



Reproduction. — The period of reproductive activity of an allied form (A. polijoph- 

 tlialma) according to Lo Bianco (1909) is from April to July. 



