20 



])i('seivatioii api)pai- in sortion as small pits (PI. I., JAg. 1). 

 ()j)(>iiin<>' ii(>a)' tliom aio the so-calliMl lioad glands, wliicli 

 in J. //If IIS f/rssn-('iisis foini a small mass of <2;'land ccdls 

 lying" in the anterior ])oition of the snout jnsi above ilie 

 iliyncliodaMim. 



(•!) The eyes vary in nuiul)er, the adult animal usually 

 liaYinc" a dorso-lateial row of ahout live on eacdi side. 

 'I'hev lie inil)edded in the tissue of the snout well below 

 the epidermis and dorsal to the head slits. Each eye 

 consists of a deep layei- of cells containing a dark hrowii 

 l)igment, ovei- which is a layer of j)yriform cells (PI. III., 

 fig 4), whose more pointed ends are drawn out into long 

 processes which are inserted into a hne nucleated mem- 

 brane. On the long processes of these ganglion (r') cells 

 may often l)e seen minute deeply-staining bodies, whilst 

 between them is a clear fluid kept in by the fine limiting 

 membiane and forming a lens. The eyes are supplied 

 by some of the cephalic nerves which enter them from 

 the pigmented side. Instances may frequently be 

 observed in which Iavo eves are incompletely separated, 

 Avhence it may pi'obably be inferred that their numl)er is 

 augmented by division of those already existing. The 

 young JJiin/s when hatched has but a single eye on either 

 side. 



THK COXXECTJVE TISSFES. 



These have l)een studied in tJie jiresent species by 

 ^lontgomery (loc. cit. p. 1), Avho distinguishes the follow- 

 ing kinds : — 



(1) ]}ran(died connective tissue cells with inter-cellular 

 substance, composing the basement membrane of the 

 external epithelium, the outei' and inner neurilemma, the 

 slu>aths around the muscular hbres, tlu^ layer immediately 

 sui rduiid iiiti' the intestine, the laver outside the endothe- 



