560 



Dr. W. C. Mantosh on 



[Feb. 22, 



anywhere on its surface, and only faint indications of pores exist in cer- 

 tain regions. Fine motionless palpocils abound all over the cuticle. 



The Hy-podenn forms a very large proportion of the tissues of the 

 flattened snout, the whole region outside the four muscular compartments 

 being occupied by it ; so that, in transyerse section, it assumes on each 

 side the shape of a long lanceolate process, which much resembles a leaf 

 ^^ith its midrib and yeins. Throughout the anterior and posterior regions 

 of the body it forms a complete sheath, with yarious thickenings, and at 

 the tip of the tail ends in two lateral styles, the glandular tissue of which 

 (as in the dorsal and yentral processes) is arranged in a yery regular 

 manner. In minute structure the hypoderm much resembles the Nemer- 

 tian cutis, presenting under pressure in the fresh animal a series of 

 flask-shaped glands or cells, from which the contents escape as clear or 

 granular globules. Moreoyer, it contains a yast niunber of bacillary cells, 

 some of which haye pigment and a large clear globule. In the hypoderm 

 lie the neryous system and neiu-al canals. 



Muscukir System. — The four longitudinal muscles of the spathulate 

 snout are arranged within a curious framework of chitinous basement- 

 tissue, which in section assumes yarious shapes — in front being like a 

 pair of spectacles, then a figure of eight, and for a considerable distance 

 yery much resembling a crown. This framework exercises an important 

 influence on the functions of the part. The central pair of muscles are 

 confined to the snout ; the lateral pass behind the mouth to constitute the 

 yentral longitudinal pair. In the preoral chamber are a strong ti'ansyerse 

 muscle (acting as the chief approximator of the sides) and a yertical muscle. 

 The muscles of the body-wall (besides the pair mentioned) are circular, 

 longitudinal dorsal, yertical, oblique, external or lateral yertical and trans- 

 yerse yentral. Anteriorly all are powerfully deyeloped for the peculiar 

 functions of the region, yiz. the compression of the blood-charmels and 

 the thrusting out of the proboscis. The muscles of the ninth body- seg- 

 ment are modified so as to form great constrictors, which haye a slightly 

 spiral arrangement. In addition to those of the body-wall, anteriorly, are 

 the long and short retractor muscles of the proboscis, and yarious bands 

 acting on the buccal and pharyngeal regions. In the posterior diyision 

 of the body the transverse yentral muscles become atrophied ; but the 

 dorsal and yentral longitudinal muscles, though constricted at the ninth 

 segment, extend throughout ; and the other muscles of the body-wall are 

 likewise present. 



Digestive System. — A T -shaped sht leads into the buccal region, then 

 follow phar}Tix, oesophagus, ventricular diyision, and intestine; while to 

 the junction of the first and second is attached the proboscis. The pha- 

 rmgeal division is fm'uished with complex muscular layers and convo- 

 luted internal sm^face, and it is thrust into the base of the proboscis in 

 full expulsion. It is probably the homologuC of the provcntriculus in such 

 Annelids as the Syllidee. The proboscis, again, is an instance of the separa- 



