216 SUMMARY OF CUBRENT RESEARCHES RELATING TO 



arises on the epithelium of the secondary body-cavity, and thus the 

 author associates the branchial heart appendage of Cephalopods, the 

 pericardial glands in Lamellibranchs, Prosobranchs, and Opistho- 

 branchs, the appendages of the dorsal vessel in Lumbriculidse, and 

 other structures in Cbsetopods. The body-cavity fluid is for the most 

 part and perhaps originally of excretory import, but also takes on the 

 respiratory and nutritive functions of lymph or hsemolymph — an example 

 of great adaptability. 



Anatomy of Megascolides australis.* — Prof. W. B. Spencer has a 

 memoir on the anatomy of the giant earthworm of Gippsland, where it 

 appears to be not uncommon, though its area of distribution is limited. 

 The best sign of the worm's presence is a very distinct gurgling sound 

 made by the animal retreating in its burrow when the ground is stamped 

 upon by the foot. It has a curious odour, resembling somewhat that of 

 creosote. When held in the hand the worm, on contracting its body, 

 throws out jets of a milky fluid ; an important, if not primary, function 

 of this fluid is that of making the burrow walls smooth, moist, and 

 slippery, and thus of enabling the animal to glide along with ease and 

 speed. Its setae appear to be of but little use to it in locomotion. Its 

 cocoons are 1^ to 2 inches in length, vary in colour according to age, 

 and contain only one embryo each. 



The largest living specimen found was 6 feet long, and the average 

 length is from 44 to 48 in., with a breadth of 3/4 in.; there are 

 from 300 to 500, or perhaps even more, segments in a sexually mature 

 worm. The setee project only slightly beyond the surface of the body, 

 and none are specially modified in connection with the male genital 

 aperture. The dorsal pores are very evident oval openings in the mid- 

 dorsal line. No nephriodiopores are visible. 



The anterior septa are enormously developed, the first fourteen 

 forming deep cups, with their concavities facing forward ; their septa 

 are connected with each other and with the body- wall by strong 

 muscular slips. It is curious to note that the insertions of the septa do 

 not correspond with the grooves separating the segments. The structure 

 of the body-wall in the non-clitellar region is that which is characteristic 

 of most earthworms, though in minor points it shows variations from 

 that of Lumhricus. In the clitellar region the skin is, as usual, much 

 modified, but differs in structure from that of Lumbricus or Microchseta. 

 The narrow elongated cells containing granules similar to those of the 

 goblet cells are absent, but there is a great development of glandular 

 cells with long ducts leading towards the exterior ; some have branched 

 bases. The glandular portion is very rich in blood-vessels, which 

 usually form distinct coils. 



Salivary glands, which are obviously modified nephridia, are described, 

 but there is no trace whatever of oesophageal glands, or of a typhlosole ; 

 the only modification of the intestine occurs in segments 12-18, where 

 the walls are highly vascular and devoid of strong muscles. 



The vascular system is comparatively simply develojped, consisting 

 of a dorsal and a ventral trunk, and transverse and dorsal vessels ; there 

 is no subneural trunk. The blood is red, owing to the presence of 

 haemoglobin, and contains very numerous nucleated corpuscles oval or 

 rounded in shape, with a diameter of about 0-0016 mm., and few more 



* Trans. E. Soc. Victoria, i. (1888) pp. 1-60 (6 pis.). 



