94: THE AMERICAN MONTHLY [April, 



13. Dictyomitra multicostata, Zittel. — Shell slender, coni- 

 cal, with prominent longitudinal ribs, and from eight to ten deep 

 strictures. Length and breadth of the joints gradually increasing, 

 the eighth joint being twice as long and broad as the fourth joint. 

 Pores regular, circular, one series in each longitudinal furrow, 

 three to four pores in each joint. 



14. Dictyomitra polypora, ZitteL — Shell slender, conical, 

 rough, with six to nine deep strictures. Length and breadth of 

 the joints gradually increasing, so that the eighth joint is twice as 

 long and broad as the third. Pores regular, circular, in transverse 

 rows in each joint, the last joint having from five to six rows. 



15. Stichocapsa tyrrelli, n. sp. — Shell smooth, slender, 

 pear-shaped, twice as long as broad, with three deep strictures. 

 Relative lengths of the four joints, i : 1.3 :4:3 ; relative breadths 

 1:2:5 ''5-5- Cephalis spherical, hyaline, without pores. Tho- 

 rax hemispherical, with four transverse rows of regular, circular 

 pores. The fourth joint is the broadest, but is shorter than 

 the large campanulate third joint. Pores in the second, third, and 

 fourth joints of equal size, and all about as wide as the bars. 



16. Stichocapsa dawsoni, n. sp. — Shell smooth, irregular, 

 ovate, with three internal septal rings, without external strictures. 

 The third joint is the largest, being more than half as long as the 

 shell. Relative lengths of the four joints, i : i : ^^ : 1 ; relative 

 breadths, 1:2:4:3. Cephalis hemispherical, hyaline, without 

 pores. The second and fourth joints small, with three transverse 

 rows of regular, circular pores. The third joint ovate, with 

 truncated poles, and from twelve to thirteen transverse rows of 

 subregular, circular pores. 



Biological Descriptions of Certain Common Hydroid 

 Animals. 



By H. L. OSBORN, 



ST. PAUL, MINN. 



{Co}tttnucd from page 6g.) 

 PODOCORYNE CARNEA }* (figS- 17--1S). 



This is a marine animal. It lives attached to the shell of the 

 spider-crab, Libinia canaliculata^ in the muddy, shelly bottoms 



* BiBLioG. — I. Claus Sedgwick, Te.\t-b. Zool., vol i, p. 237. 



2. Lankester, E. IJrit., i.x, p. 560. 



3. Oegenbaur, Comp. Anat., p. 94. 



4. Parker, Elementary Zoology, p. 236. 



5. Lang, Text-Kook of Zoology. 



6. Romanes, Jellyfish, Starfish, etc., p. 10. 



Explanation of Figures of Podocoryne. 



Fig. 17. Podocoryne, from nature, showing the reproductive person with the manubrium and 

 tentacles, and the clustered medusa buds in various stages of development, showing the rhizoid, 

 or stolon attached in this case to the shell of the spider-crab. 



Fig. 18, Podocoryne from nature, the medusa : rv, radial vessel ; vel, velum ; S.ku, sensory 

 organ at base of tentacle, eyespot; mar. ten., marginal tentacles in two sets, four shorter ; man, 

 the manubriums inside the bell ; or, the ovary in the ectoderm on the manubrium. 



