560 SUMMARY OF CURRENT RESEARCHES RELATING TO 



another circular vessel at the anterior portion of the trunk, immediately 

 behind that which lies between the collar and the trunk ; (4) confluence 

 of the four most anterior pairs of gill-pouches into a common cavity on 

 each side, discharging to the exterior through a common gill-pore, with 

 the collar-pores distinct at the anterior wall of the common cavities ; 

 (5) communication of the lateral vessels with the dorsal vessel imme- 

 diately behind the last gill-slits ; (6) occurrence of circular muscle- 

 fibres at the anal region, just external to the longitudinal muscle-fibres 

 upon the gut-wall ; (7) dorso-terminal position of the anus. 



Though the species is to be ranked, from its general structure, under 

 the genus Balanoglossus Delle Chiaje among the Ptychoderid®, it has 

 some features characteristic of other groups of the Enteropneusta. 



Variation in Platystrophia Lynx.* — E. E. Cumings and A. V. 

 Mauck have made a quantitative study of variation in this fossil 

 Brachiopod. The species is extremely variable, exceptionally abundant 

 and well-preserved, and thus well suited for quantitative study. Such 

 an investigation is more warranted because of the different opinions 

 current as to the taxonomic importance of several of the forms under 

 which Platystrophia presents itself. 



Echinoderma. 



Extraordinary Animal. f — H. L. Clark reports, under the above 

 title, on a strange specimen dredged by the " Albatross " in 1588 

 fathoms off the Queen Charlotte Islands. It is probably a monstrosity, 

 but of what ? It has a firm external skeleton, which completely en- 

 closes it, and two parts with no internal communication. The smaller 

 upper part is nearly cylindrical, bounded by a calcified membrane, 

 strengthened by seven transverse rib- or hoop-like thickenings, which 

 are lighter in colour than the membrane. At the posterior end are two 

 very short longitudinal ribs of similar appearance. The skeleton of the 

 lower part is made up of numerous small, closely united plates of unequal 

 size, and of no definite arrangement, each bearing a blunt spine about 

 1 mm. in length. Similar spines occur on the upper part of the auimal, 

 like Echinoid spines microscopically, but not jointed to the skeleton. 

 Apart from the spines, the whole external appearance of the lower part 

 is like the Holothurian, Sphaerothuria or Echinocucumis. 



The upper chamber containtd a much-branched gland, resembling 

 the gonad of a Holothurian. The lower chamber is almost wholly filled 

 with what appears to be part of a digestive-tube with a large lumen. 

 There is no evidence of mouth, anus, locomotor organs, water-vascular 

 system, nerves, or sense-organs, so far as macroscopic observations show. 

 The specimen, light brown in colour, is about 15 mm. in length, and 

 the greatest height is about the same. Such an extraordinary animal 

 gives one pause, and makes one feel as if there were something wrong 

 in Nature or in man's device. The author is inclined to call it a 

 monstrous Holothurian, allied to Sphaerothuria. 



Body-Wall and Gut-Wall in Echinoderms.^ — E. Herouard gives 

 an account of the body-wall in Holothuroids, and compares it with that 



* Amer. Journ. Sci., xiv. (1902) pp. 9-16 (3 pis.). 



t Zool. Anzeig., xxv. (1902) pp. 509-11 (1 fig.). 



\ Bull. Soc Zool. France, xxvii. (1902) pp. 131-8 (1 fig.). 





