306 



SCIENCE. 



[Vol. II., No. 31. 



his followers. Sueli are the iron Innuits of 

 the unmanned igloos of the Arctic. 



A recently' constructed igloo is more comfort- 

 able than one long used, the alternating heat 

 and cold of the day and night soon converting 

 the latter into a translucent mass of ice, that 

 becomes uncomfortabl}^ chilly on a cold night ; 

 besides, the steam from the cooking and the 

 moisture from the breath congeal upon the 

 roof, and, in the course of ten or twelve days, 

 become so thick as to form a base for a 

 constant liliputiau snow-storm, which is disa- 

 greeable beyond measure. One of the most 

 conspicuous comforts of arctic travelling is the 

 constant changing of igloos. 



(To be coiitiimed.) 



BALFOUR'S LAST RESEARCHES ON 

 PER/PA TUS. 



At the time of his death, the late lamented Prof. 

 F. 51. Balfour was engaged upon an investigation of 

 the anatomy and development of Peripatus, the low- 

 est known form of Ti-acheata (insects). Unfortu- 

 nately, he left his work far from complete; but two 

 friends, Mr. Sedgwick and Professor Moseley,' both 

 thoroughly competent, have undertaken and com- 

 pleted the grateful task of editing what could be 

 gathered from Balfour's material. We have, how- 

 ever, hardly more than a descriptive account of Ihe 

 anatomy and development of the animal. We miss 

 the fruitful thought with which Balfour enriched his 

 writings before committing them to the press. 



The article is published in the April number of the 

 Quarterly journal of microscopiaal science, and is ac- 

 companied by numerous beautiful plates. A portion 

 of these were drawn by Miss Balfour. Their e.Koel- 

 lence graces this quiet expression of a sister's close 

 relation to a gifted brother. 



Balfour's investigations were directed especially 

 upon Peripatus capensis. The memoir opens with 

 a careful description of the external characters of the 

 species. The account of the legs is the first satisfac- 

 tory one published. The number of legs is variable, 

 but usually there are seventeen pairs. Each leg has 

 the form of a cone, with a pair of claws at the apex: 

 it bears a succession of rings of papillae, but towards 

 the lip the papillae in part fuse together to form three 

 ventrally placed pads. The foot is distinct, being 

 separated by a constriction from the upper part of 

 the limb, and has several pads upon its ventral sur- 

 face, and bears the two conical recurved claws. On 

 the middle of the ventral line of junction of the leg 

 with the body lies the opening of the segmental or- 

 gans. The disposition of this opening on the fourth 

 and fifth legs is slightly different. The last leg has 

 a papilla with a slit-like gland opening at its apex. 

 The gland itself is large, and runs far forward, and is 

 probably a modified crural gland. 



Part II. is a monograph of the internal anatomy. 

 In the alimentary canal, a nearly straight tube slightly 



longer than the body, five parts may be distinguished. 

 1. The buccal cavity. Its opening is surrounded by 

 a tumid lip, covered by a soft skin raised into papilli- 

 form ridges. Attached to the median dorsal wall of the 

 cavity is a muscular protuberapce (tongue), covered 

 by the oral epithelium, and furnished with oigaus of 

 special sense, like those in the skin, and with chitinous 

 teeth. On each side of the tongue is placed the jaw, 

 with recurved chitinous teeth. The jaws are, no 

 doubt, modified limbs: their structure and action are 

 miimtely described. The salivary glands open into the 

 buccal cavity by a short common duct, are variable in 

 length, but stretch usually two-thirds the length of 

 the body. They consist of two parts: the first runs 

 backward as a wide, straight tube; the second runs 

 forward and upward, is small in diameter, and ap- 

 parently branching in the figures, though the fact is 

 not mentioned in the text. The anterior end of the 

 first part serves as a duct, and is lined by a cubical- 

 celled epithelium; while the rest of the same part is 



Fig. 1. Horizontal section tlirougli the hcfid; trp, traehe.al pit; 

 ««/, Balivary gland; J/, moutli; .s tf, common salivary duct; 

 e/ijaw; cj.;, outt-r. jaw, or muscular portion ; between the two 

 jaws lies the sectioa of the tongue. 



glandular, and lined by verjf elongated epithelial cells 

 with their nuclei at their bases. 2. The pharynx is 

 a highly muscular tube, with a triangular luinen, 

 which extends from the mouth to about half way be- 

 tween the first and second pair of legs. (It appears 

 to me that the author is in error when he statf s that 

 such a structure is not characteristic of insects.) .3. 

 The oesophagus, on the dorsal wall of which occurs 

 the junction of the two sj^mpathetic nerves. 4. The 

 stomach, by far the largest part of the alim&tary 

 tract, has its walls irregularly, not segmentally, folded. 

 The walls themselves are composed principally by the 

 internal epithelium, the cells of which are elongated, 

 fibre-like, with their nuclei about one-fourth of the 

 way from the base; and around their bases are short 

 cells irregularly scattered, and having round nuclei. 

 5. The short rectum is chiefly remarkable because the 

 circular muscular layer is outside the internal layer 

 formed of isolated longitudinal bands. 



The nervous system is particularly interesting; for 

 it consists of two ventral cords united by numerous 

 transverse bauds, and having an enlargement corre- 



